This type of ear pad 51 based on the conventional technology has, as shown in FIGS. 6 and 7, each showing the case in which the ear pad is applied to an ear plug, a fit section 53 slanted to the rear edge side and comprising, for instance, a thin and spherical silicone rubber sheet provided at a tip of a hollow and cylindrical basic body 52 and expanding toward a rear edge of the basic body 52, and because of the structure as described above, the ear pad can be fit in an auditory meatus with this fit section, and also provides flexibility to the size of an auditory meatus in the radial direction.
When the ear pad 51 as described above is inserted and set in an auditory meatus, the ear pad can be set therein because the fit section 53 provides softness, but as there is a tapered portion with the diameter gradually becoming smaller toward the depth thereof in the auditory meatus at its entrance, when the ear pad is inserted, the force P acting to crush the fit section 53 generates the force F to push back the ear pad as shown in the figures, so that the ear pad easily drops out. Only the frictional force between an external surface of the fit section 53 and the inner wall of the auditory meatus acts against the force P for pushing back the ear pad. Therefore, if the fit section 53 of the ear pad 51 is too soft, the frictional force becomes too small, and the ear pad easily drops out. On the contrary, if the fit section 53 is too hard, it presses the inner wall of an auditory meatus, and causes pain, even if the ear pad is set there only for a short period of time.
FIG. 8 is a cross-sectional view showing the situation where the fit section 53 of the ear pad 51 is deformed inside an auditory meatus. The form and size of an auditory meatus vary in each person, and the dimensional relations are delicate, and when the fit section 53 is inserted into a deeper position than the desired one, or when the fit section 53 is larger than the auditory meatus, there is no escaping space for deformation because of the monolithic structure of the spherical portion, so that deformation occurs to generate a clearance 55 on a portion of a periphery of the fit section 53 with the sound insulating properties degraded. Even if three types of ear pads, namely ear pads with small, medium, and large size are prepared to respond to the individual difference, at present it is difficult to completely overcome this problem. In addition, when the ear pad is set in an auditory meatus, an external surface of the fit section 53 closely contacts the internal wall of the auditory meatus on its entire surface, so that dermatitis often occurs in people having sensitive skin, and further if the ear pad is set for a long time, stimulation easily occurs due to becoming stuffy, and the ear pad easily drops out due to sweat or fat.
The present invention was made in the light of the circumstances described above, and it is an object to provide an ear pad having a softness and adaptability to being set in an auditory meatus without stimulating its sensitive portions, which can flexibly respond to individual differences and also can smoothly be set but is little affected by the decrease in the frictional force due to sweat or fat, which seldom generates becoming stuffy or dermatitis, even in people having sensitive skin, which can be used without causing any discomfort and is resistant even to the force acting in the releasing direction so that it hardly drops out, which can improve the capability of attenuating noises coming from the outside, and further, which is excellent in the sealing performance as well as in the sound insulating properties and also to provide an earphone with the pad.